This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The goal of this research is to assess in vivo micro-CT to improve cardiac imaging in rodents. The imaging studies will assess the way the micro-CT can perform 3D imaging of the heart in different phases of the ECG cycle. Images can be used to quantify the normal and dysfunctional cases when used with heart disease models in mice and rats.